Fisher D500243X012 - Manual (Page 20)

Instruction Manual
D500243X012
1035/El-O-Matic Actuator
August 2012
20
Spring Return E Series Actuators
Spring return E Series actuators use from two to a maximum of six springs. One, two, or three springs are inserted into
each end cap (see figure 8). Refer to the nameplate to verify the number of springs required.
Each end cap spring pack incorporates a travel stop adjustment screw (key 37). This may be used to adjust the end of
the stroke for valve seating in either the “fail open” or “fail closed” arrangements.
1. When installing used springs in a spring return actuator, ensure that the springs are replaced in the identical
position from which they were removed.
2. If a spring return actuator is being repaired due to spring failure, replace all the springs in the actuator.
3. To assemble the spring assembly, install the spring(s) into the end cap. Be sure that all springs are seated correctly
in the end cap (key 5) and in the spring holder (key 9). Place the spring holder and washer on top of the springs, and
install the adjustment screw (keys 34 and 37).
4. Place the end cap bolts through the retention holes of the end cap. If converting a double acting unit to a spring
return unit, be sure to use new end cap screws (key 25, figure 12).
5. Engage the bolts with the tapped holes in the actuator body by forcing down slightly on the cap. Tighten each bolt
in small, equal amount of turns, compressing the springs equally.
Spring Return P Series Actuators
Spring return actuators use from four to a maximum of fourteen springs. One through seven springs are inserted into
each end cap (see figure 9). Refer to the nameplate to verify the number of springs required.
1. When installing used springs in a spring return actuator, ensure that the springs are replaced in their identical
position in the end cap from where they were removed.
Note
When less than the standard number of seven springs are used in each end cap, the springs should be positioned as shown in
figure 9.
2. If a spring return actuator is being repaired due to a failed spring, replace all the springs in the actuator.
3. Ensure that the pistons are stroked fully inward, towards the center of the actuator (this may be done by rotating
the actuator shaft with a wrench).
4. When replacing the springs in a P Series spring-return actuator, position the actuator so that it stands on one end.
5. Place the springs on the piston face, engaging them with the alignment nibs cast into the piston.
6. Place the end cap over the springs. Align them with the corresponding nibs which are cast into the end cap.
7. If converting a double acting unit to a spring return unit, be sure to use new end cap screws (key 25, figure 12).
Install the end cap screws.
8. Engage the screws with the tapped holes in the actuator body by forcing down slightly on the cap. Tighten each
bolt in small, equal amount of turns, compressing the springs equally.
Installing the Bypass Valve
The optional bypass valve should be used when pressure needs to be stabilized between port A and port B (see figure
10). The following steps provide installation of the bypass valve. Removing the bypass valve simply requires
performing these steps in the reverse order.